Is CVE-2026-61511 actively exploited?

Yes. Previdian has observed exploitation attempts targeting this CVE. Confidence is confirmed.

What exploitation activity has Previdian observed?

Previdian sensors have observed 2 exploitation attempts, 2 unique attacker IPs, and 1 country targeting CVE-2026-61511. First observed Aug 27, 2026; last observed Aug 28, 2026.

Which versions are affected?

CVE-2026-61511 affects vBulletin vBulletin. Reported affected versions include 5.0.0 to <= 5.7.5, 6.0.0 to <= 6.2.1, and 6.2.2.

How should organizations remediate it?

Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.

No. CVE-2026-61511 is not currently listed in CISA KEV.

Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2026-61511

Q: How should organizations remediate it?

Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.

Q: Is it in CISA KEV?

No. CVE-2026-61511 is not currently listed in CISA KEV.

vBulletin < 6.2.2 Eval Injection RCE Remote Code Execution

vBulletin / vBulletin · 5.0.0 to <= 5.7.5

View live feed Monitor via API Watch CVE-2026-61511

Severity: CVSS 9.3 · Critical
Confidence: Confirmed
Exploit status: Observed in sensors
EPSS: 70.8%
First observed: 27 Aug 2026
Last observed: 28 Aug 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-61511 is an unauthenticated vulnerability affecting vBulletin vBulletin. vBulletin 5.x through 5.7.5 and 6.x through 6.2.1 contains an eval injection vulnerability in the vB5_Template_Runtime::runMaths()...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence.

Who is affected?

vBulletin / vBulletin 5.0.0 to <= 5.7.5.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

vBulletin < 6.2.2 Eval Injection RCE Remote Code Execution

vBulletin 5.x through 5.7.5 and 6.x through 6.2.1 contains an eval injection vulnerability in the vB5_Template_Runtime::runMaths() method within the template runtime that allows unauthenticated remote attackers to execute arbitrary PHP code by supplying crafted input through the pagenav[pagenumber] parameter.

Attackers can exploit the insufficiently restrictive regex filter by using phpfuck-style encoding with permitted characters to inject and execute arbitrary PHP code via the unauthenticated ajax/render template route without any authentication.

Vendor Product Affected Status

vBulletin vBulletin Through 5.7.5 Affected

vBulletin vBulletin Through 6.2.1 Affected

vBulletin vBulletin 6.2.2 Unaffected

View vendor advisory

Published: 27 Jul 2026
Exploitation Reported: 27 Aug 2026
Attack vector: Remote
Complexity: Low
Privileges: None
User interaction: None

CVE References

CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2026-61511
Third-Party Advisory — vulncheck.com vulncheck.com · Third-Party Advisory https://www.vulncheck.com/advisories/vbulletin-eval-injection-rce-via...
Karma(In)Security Disclosure karmainsecurity.com · Exploit https://karmainsecurity.com/KIS-2026-13
SSD Secure Disclosure ssd-disclosure.com · Exploit https://ssd-disclosure.com/vbulletin-runtime-template-runmaths-preaut...
6.2.1, 6.2.0, 6.1.6 Security Announcement forum.vbulletin.com · CVE Record https://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-a...
6.2.2 Release Notes forum.vbulletin.com · CVE Record https://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-a...

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

Previdian

Recorded 27 Aug 2026

Independent exploitation attestation added to the Previdian record.

Active exploitation observed

Previdian sensor

First observed 27 Aug 2026

First-party sensor telemetry confirms matching exploitation attempts.

Proof of concept available

GitHub

Recorded 28 Jul 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access

Source	Added
Previdian First	2026-08-27 13:06 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Aggregate observations show the scale, recency, and distribution of activity without overstating sparse data.

Attempts observed

Unique attacker IPs

Attacker countries

Sensors observed

Exploitation attempts over the last 8 days

Daily events observed by Previdian sensors

Updated 02 Sep 2026

26 Aug 27 Aug 28 Aug 29 Aug 30 Aug 31 Aug 1 Sep 2 Sep

First observed 27 Aug 2026 · Last observed 28 Aug 2026

Pro adds sensor region and window summaries. Enterprise adds raw IPs, paths, User-Agents, and payloads.

Request telemetry access

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets: 1
User-Agents: 2

Raw values available in Pro and Enterprise.

Scanner coverage

Nuclei template detected 25 Aug 2026.

View Nuclei template

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner	Reference	Detected
Nuclei	https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-61511.yaml	25 Aug 2026

Risk and context

Severity, weaknesses, and research context

CVSS v4.0

9.3 Critical

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS

70.8%

Weaknesses

Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection') CWE-95

All CVSS Scores

CVSS v4.0 9.3 Critical

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v3.1 9.8 Critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

vBulletin runtime template runMaths pre-auth RCE

pruva · Created 2026-07-27 17:08:26 UTC

Severity: CRITICAL | CVE: CVE-2026-61511 | Package: vBulletin

vBulletin runtime template runMaths pre-auth RCE

pruva · Created 2026-07-27 17:08:26 UTC

Severity: CRITICAL | CVE: CVE-2026-61511 | Package: vBulletin

vBulletin 6.x - Remote Code Execution

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

27 Aug 2026
Observed by Previdian sensors

Evidence-backed exploitation signal
27 Aug 2026
Indicators of compromise added (2)

Indicators of compromise recorded
25 Aug 2026
Nuclei template available

Scanner coverage available
27 Jul 2026
Public PoC available

Public proof-of-concept code published
27 Jul 2026
CVE published

Vulnerability disclosed publicly
10 Jul 2026
CVE ID reserved

Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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Evidence confidence and provenance
First-party sensor telemetry
PoC and scanner references
Affected versions and enrichment
Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-61511

Free JSON includes basic KEV fields

{
  "cve_id": "CVE-2026-61511",
  "confidence": "Confirmed",
  "cvss_score": 9.3,
  "cvss_estimated": false,
  "epss_score": 0.70766,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 2, "sensors": 2 }
}

CVE-2026-61511

vBulletin < 6.2.2 Eval Injection RCE Remote Code Execution

Tags

CVE References

Exploited in the wild

Active exploitation observed

Proof of concept available

Known exploited vulnerability sources

Observed signals

Scanner coverage

Virtual patch status

Attacker IP Indicators

Scanner Artifacts

Weaknesses

All CVSS Scores

Potential Proof of Concepts

Observed by Previdian sensors

Indicators of compromise added (2)

Nuclei template available

Public PoC available

CVE published

CVE ID reserved

Automate this intelligence